1. Field of the Invention
The present invention relates to an outside monitoring device which monitors a state of a surrounding area of a mobile robot. Especially, the present invention relates to a monitoring device for a mobile robot that allows extending a detectable range in the surrounding area of mobile robot.
2. Description of Relevant Art
Conventionally, a mobile robot (hereinafter referred to as “robot”) equips with various kinds of an outside monitoring apparatuses for monitoring an external state. In Japanese unexamined patent publication JP2003-266353, for example, various kinds of sensor, e.g. an image pickup unit, a microphone, a touch sensor, and a light sensor, are provided on the robot, and the outputs from these sensors are used for actuating the robot.
In the case of the robot disclosed in Japanese unexamined patent publication JP2002-154084, an image pickup device is provided on a head of the robot whose head is being movable around a vertical axis and a horizontal axis. In this robot, the occurrence of the distortion of the image that is caused due to the change of the direction of eyes (camera) is controlled by constantly synchronizing the turn of the head of the robot and the direction of the eyes of the image pickup device.
In the above described apparatuses disclosed in JP2003-266353 and JP2002-154084, the monitoring is performed using an image pickup device (camera) which serves as an outside monitoring device and which are directed in a fore direction.
That is, the monitoring of a target object, e.g. shape of the target object, that is located in front of the image pickup device is performed using the image pickup device (camera).
Therefore, if the head of the robot is directed to a fore direction, the monitorable region is limited to the region in front of the robot. Thus, the target object which approaches the robot from behind and the target object at the back of the robot are not detected by the robot.
Additionally, if a camera is used for detecting the movement of the target object, a complicated processing, such as the comparison between the previous image and the next image, is required.
Therefore, the outside monitoring device for a robot that can monitor a state of a surrounding area of the robot and measure the direction of a target object by simple processing has been required.